What Birds Are Going Extinct? A Look at the Crisis

Roughly one in eight of the world’s known bird species is at risk of extinction, and close to half of all bird species are experiencing population declines. According to IUCN Red List assessments, about 13% of the 11,188 evaluated bird species face some level of extinction threat, a figure that spans critically endangered parrots in Indonesia to seabirds vanishing from remote Atlantic colonies.¹ The crisis is not limited to rare species most people have never heard of. Common birds, the ones that fill suburban backyards and agricultural fields, are disappearing at staggering rates too.

How Bad Is the Decline, in Numbers

North America alone has lost roughly 3 billion individual birds since 1970, a drop of about 29% of its total bird abundance. That estimate, drawn from decades of population surveys and confirmed by weather radar tracking of migrating flocks, captures the loss not just of threatened species but of once-common groups like sparrows, warblers, and blackbirds.² This matters because extinction does not begin when the last individual dies. It begins with the steady erosion of abundance that weakens ecosystems long before a species formally disappears.

The rate at which species are being lost far exceeds what would happen naturally. Before humans altered the landscape, bird extinctions occurred at a background rate of roughly one species per million species per year. By the time you account for species that vanished before scientists could document them, the recent extinction rate climbs to around 100 times that baseline.³ In the most recent decades, the rate has moderated somewhat, to under 50 times the baseline, but only because conservation programs have actively prevented additional losses. Without those programs, the rate would be closer to 150 times background.³

Where Extinctions Concentrate

Islands have been ground zero for bird extinctions throughout recorded history. Although fewer than one-fifth of the world’s bird species live exclusively on islands, over 90% of documented bird extinctions in modern times have occurred on islands.⁴ The Hawaiian Islands alone account for 36 extinct bird taxa, followed by mainland Australia and its surrounding islands at 29, the Mascarene Islands (home of the dodo) at 27, New Zealand at 22, and French Polynesia at 19.⁵

The reasons are straightforward. Island birds evolved without mammalian predators, so they never developed the wariness or flight responses that mainland species rely on. Many became flightless or ground-nesting. When humans arrived and brought rats, cats, and other mammals, island species had no defenses. On continental landmasses, the extinction rate has historically been far lower, somewhere between 1 and 6 times the background rate, while on islands it has ranged from about 100 to more than 800 times the background rate.⁶ Island populations remain more prone to extinction than mainland populations, in part because small, isolated gene pools make them vulnerable to inbreeding and environmental shocks.⁷

That said, the extinction wave has not been limited to remote atolls. On the UK Overseas Territories, invasive house mice, feral cats, and rats continue to threaten four critically endangered endemic birds on Gough Island, St Helena, and Montserrat, and have already caused massive reductions in seabird colony sizes across the territories.⁸ Cats are a threat on the mainland too, especially for vulnerable species in localized areas where even small numbers of predation deaths can push a population over the edge.⁹

The Biggest Drivers of Decline

Habitat destruction, particularly for agriculture, is the single most damaging force behind global bird declines. A major analysis of bird population trends identified agriculture, urbanization, climate change, and forest loss as the primary drivers.¹⁰ In Europe, the evidence is especially stark: farmland practices, and in particular the heavy use of pesticides and fertilizers, have been identified as the main pressure behind population declines, with insect-eating birds hit hardest.¹¹ When you drench fields in chemicals that kill insects, the birds that eat those insects starve.

Farmland birds that depend on open habitats, like meadows and grasslands, are in the worst shape. Species closely tied to open landscapes show the steepest declines, while those that favor continuous woodland tend to be holding steady or even increasing.¹² The Red-backed Shrike, once a common sight across Central Europe, illustrates this trend. Over more than 30 years, the species has neared local extinction in some strongholds as meadows have been converted to cropland or abandoned and overtaken by shrubs.¹³

In the tropics, the combination of deforestation and cropland conversion poses an even greater threat, because tropical birds tend to be more diverse and have smaller ranges. Projections suggest that land-use change in tropical and subtropical regions is responsible for more than half of projected range contractions and, by itself, causes twice as many species to lose over half their range compared to climate change alone in those latitudes.¹⁴ Forest fragmentation in the Amazon provides a vivid case study: when patches of rainforest are isolated by even a few hundred meters of cleared land, understory insect-eating birds vanish rapidly. Obligate army-ant followers disappear within two years, and mixed-species flocks fall apart within two to three years.¹⁵ Some recolonization is possible if secondary growth is allowed to develop around fragments, but only for a subset of species.¹⁶

Climate Change and the Mismatch Problem

Rising temperatures are not just a future threat for birds. They are already reshaping migration timing in ways that can be lethal. Many migratory species time their spring arrival at breeding grounds to coincide with peak insect availability, which in turn is driven by temperature and plant growth. As springs arrive earlier at breeding sites, birds that winter thousands of miles away have no way of knowing. They leave on their old schedules and arrive too late.

Species with the greatest “thermal delay,” meaning the biggest gap between when they arrive and when the local environment has already warmed and surged with insect life, have shown the largest population declines. This pattern holds even after accounting for other ecological factors.¹⁷ The European pied flycatcher is a sobering example: despite advancing its egg-laying date by 10 days, the shift has been insufficient to keep pace with spring changes, and some populations have declined by 90%. Models predict that by 2070, pied flycatchers will need an additional four days to complete their migration, potentially widening the mismatch further.¹⁸

Seabirds Under Pressure

Seabirds are among the most threatened groups on the planet. Of the 359 recognized seabird species, roughly 31% are globally threatened and another 11% are near threatened. The major threats include invasive species at nesting colonies, bycatch in commercial fishing gear, overfishing that depletes their food supply, and climate change.¹⁹ Bycatch, where birds get tangled in longlines or trawl nets and drown, remains the most widespread at-sea hazard.

Avian influenza has recently added an entirely new layer of risk. During the spring and summer of 2022, a severe outbreak of highly pathogenic H5N1 virus killed an estimated 40,000 wild birds in eastern Canada alone, though actual mortality was certainly higher because deaths at sea and in remote areas went unreported. Northern Gannets bore the worst of it, with over 25,000 estimated deaths, followed by Common Murres and American Common Eiders. For Northern Gannets and Common Eiders, the losses were severe enough to threaten population-level impacts.²⁰ Earlier outbreaks in Europe had already demonstrated the virus’s capacity for mass die-offs: during the 2016–2017 winter, H5N8 killed roughly 13,600 wild birds in the Netherlands, mostly tufted ducks and Eurasian wigeons.²¹ These are long-lived species that reproduce slowly, so mass mortality events set populations back by years or decades.

The Wildlife Trade

Trapping wild birds for the pet trade and other uses has significantly contributed to declines in several bird groups. Parrots are the most visible victims. High global demand for parrots as pets has fueled heavy illegal harvesting, particularly in countries like Indonesia, where researchers found that trade volume is driven by a combination of how attractive a species is, how accessible it is to trappers, and whether it can be legally exported.²² But parrots are far from the only group affected. A global assessment of birds in trade found that falcons, hawks, eagles, hornbills, owls, and waterfowl are all traded at high rates. Songbirds, the order Passeriformes, account for the highest overall number of traded species of any bird group, despite having relatively low representation in international trade protections.²³

Light Pollution and Building Collisions

Millions of nocturnal migrants die each year from crashing into brightly lit buildings and communication towers. Research at a single building complex in Chicago found that the number of fatal collisions spiked during large migration events when the building was brightly illuminated and wind conditions funneled birds along the lakeshore.²⁴ The birds most affected are species that use flight calls during nocturnal migration; among these, collision frequency correlated strongly with the amount of artificial light. Species that do not use flight calls collided far less often and showed no relationship with light levels at all.²⁵ The practical implication is clear: turning off unnecessary lights during peak migration periods can meaningfully reduce this source of mortality, and several cities have started “lights out” programs for exactly this reason.

What Happens When Birds Disappear

Birds are not just charismatic wildlife. They perform ecosystem services that communities and entire landscapes depend on, including pollination, seed dispersal, and decomposition. When bird populations decline, these processes weaken.²⁶

One of the clearest demonstrations comes from New Zealand, where the functional extinction of native bird pollinators has caused a cascade of effects on the plant Rhabdothamnus solandri, a shrub that depends on birds for pollination. On the mainland, where bird pollinators have been wiped out, seed production per flower has dropped by 84% and there are 55% fewer juvenile plants per adult compared to nearby island sanctuaries where bird populations remain healthy.²⁷ The plant itself is heading toward decline because nothing has replaced its missing pollinators.

Vultures offer an even more dramatic case. In South Asia, populations of Gyps vultures crashed by over 95% due to poisoning by diclofenac, a veterinary painkiller that accumulated in cattle carcasses. The ecological fallout was severe: with vultures gone, carcasses rotted in the open, and populations of feral dogs and rats surged to fill the scavenging gap, increasing the potential for transmission of rabies, brucellosis, and tuberculosis.^{28 29} Regional governments banned diclofenac in 2006, but vulture populations have been slow to recover.

Conservation That Works

The picture is not entirely bleak. Targeted conservation efforts have prevented a meaningful number of extinctions. Between 1993 and the early 2020s, researchers estimate that conservation action prevented somewhere between 21 and 32 bird species from going extinct. Given that 10 bird species did go extinct during that same period, the extinction rate would have been three to four times higher without intervention.³⁰ An earlier, more focused assessment examined 16 species that would have likely vanished between 1994 and 2004 without dedicated programs. The average minimum population of these species rose from 34 to 147 breeding individuals over that decade, and the proportion with increasing populations went from about a third to over 80%.³¹

These programs typically involve a combination of captive breeding, predator control at nesting sites, habitat restoration, and legal protections. The successes are real, but they also reveal a tension: the species brought back from the edge often remain genetically fragile. Populations that pass through severe bottlenecks lose genetic variation and accumulate harmful mutations. The pink pigeon of Mauritius, a conservation icon whose numbers rebounded from near zero, illustrates this problem. Despite its demographic recovery, its genetic diversity continued to erode, and its effective population size remained roughly a tenth of its census count. Simulations suggest the species will likely go extinct in the wild within 100 years without ongoing management to counteract inbreeding.³²

A similar pattern has appeared in the Stitchbird (or hihi) of New Zealand and the South Chatham Island Black Robin recovery. Managers sometimes face a painful irony: by successfully boosting survival and reducing competition, conservation can relax the natural selection pressures that would normally purge the most damaging mutations. In one endangered island songbird, researchers found a three-fold decrease in genetic diversity between historical and modern samples, along with an increase in genetic load, the accumulation of harmful variants, compared to museum specimens collected before the bottleneck.³³ Genetic rescue, moving individuals between isolated populations to introduce fresh variation, is increasingly seen as a necessary complement to habitat protection and breeding programs.³⁴

New Tools for Finding What Is Left

One persistent challenge in bird conservation is figuring out what still exists, in what numbers, and where. Traditional field surveys are expensive and limited by terrain and weather. Automated acoustic monitoring has started to change that equation. In Hawai’i, where several critically endangered forest birds survive in tiny, remote populations, continuous real-time acoustic systems are now able to detect species like the ‘Akē’akē (Band-rumped Storm-Petrel) and Nēnē (Hawaiian Goose) with near-perfect accuracy, identifying their calls from ambient recordings and steadily improving as models are updated.³⁵

Similar approaches are being used in Indonesia’s Gandang Dewata National Park to track the endangered Snoring Rail, a secretive marshland bird that is nearly impossible to survey visually. Acoustic recorders placed around the park detected the species at every site, with most calls coming in the morning and midday hours and classification accuracy high enough to generate population and distribution estimates from sound data alone.³⁶ These tools do not replace human fieldwork, but they expand coverage dramatically, especially in the dense tropical forests and remote islands where the most threatened species tend to live. For species that are essentially invisible to the human eye, being heard is now enough to be counted.